The present invention relates to a flexible barrier cover assembly for use with "reach-in" merchandiser type of refrigerated display cases or cabinets used primarily in retail food and supermarket outlets. The operation of the barrier cover is controlled automatically according to the occurrence of selected conditions.
The term "refrigerated", in accordance with the present invention is intended to incorporate those cases maintained at a temperature at or in excess of 32.degree. F., such as display cases utilized for the display of milk and fresh foods, and those cases maintained below 32.degree. F., such as frozen food cases.
An increasing demand being made by managers of retail food stores or outlets is the reduction of the energy consumption of refrigerated display cabinets which are used in such outlets. Various approaches have been used to conserve the energy required to operate these display cabinets. When the display cabinet is operated as an open-top or an open-front cabinet to permit freer customer access to the stored products the refrigerated air contained within the cabinet is in direct contact with the ambient air. Heat and moisture transferring from the ambient air into the air bands circulated within such open cabinets are responsible for a large fraction of the heat loads. Restriction of this transfer process by the use of heat barriers is thus considered desirable.
Open-top and open-front cabinets incur high operating energy costs both during the customer use periods when the retail outlet is open and those non-use hours when the outlet is closed. One approach to the problem of the high energy expense of operating the refrigerated cabinet during non-use time periods is shown in U.S. Pat. No. 4,109,484 to Cunningham and 4,141,611 to DeLeon in which protective barrier covers are manually hung over the access opening of refrigerated display cases by the retail employees.
Another approach to solving this problem has been to incorporate a manually movable cover means within the structure of the refrigerated display cabinet as shown by U.S. Pat. Nos. 2,773,357 to Canter; 3,186,185 to Bently et al; 3,241,899 to Donker; 3,403,525 to Beckwith et al; and 4,117,698 to Vogel.
A problem with the devices disclosed in the patents set forth above is that the barrier covers must be manually moved into the blocking positions which then necessitates the retail outlet personnel remembering to take this action at the beginning of the non-use time period. In modern retail food supermarkets there are a large number of refrigerated display cabinets which then requires a significant time expenditure on the part of the personnel in order to effect the potential energy savings by the use of such manually employed barrier covers. The twice daily necessity for moving the barrier covers subjects them to tearing, ripping and general physical deterioration. Storage of such large sheet materials is also regarded as a problem by the operating managers and personnel.
Another, somewhat more complicated solution, to this problem is suggested in U.S. Pat. No. 2,994,572 to Morrison in which a photoelectric cell control circuit is employed to open barrier doors for permitting customer access to the stored products. This type of system requires a large portion of the refrigerated display cabinet structure to be employed as a door storage space. The control circuitry is also complicated.
Various cover, lid, and door arrangements have been proposed for refrigerated display cabinet as shown by U.S. Pat. Nos.: 2,001,106 to Mullen; 2,041,258 to Mitchell; 2,081,048 to Bate; 2,175,839 to Hopkins; 2,518,134 to Fredenhagen et al; 2,669,851 to Pichler; 2,694,613 to Williams; 3,273,585 to Patch; 3,359,050 to Dongus; 3,360,316 to Swanson; and 4,186,790 to Schenker et al. However, these patents do not provide for the automated operation of the cover means to protect the refrigerated air from contact with the ambient air without the attendance of store personnel.
A flexible door for a storage cabinet in which the door is operated by motor means is shown in U.S. Pat. No. 3,317,259 to Otis. However, the cabinet is not refrigerated and the motor is controlled by means of a manually operated switch which does not permit automated openings and closings controlled by selected use conditions. This patent does not disclose the automated operation of protective barrier covers for refrigerated display cabinets in retail food outlets. Yet, in order to derive the potential energy conserving advantages from such covers practice has indicated that the present manually operated covers are inadequate.
The above difficulties are overcome by the automated conserving barrier covers of the present invention in a manner to realize the potential energy savings of such covers and to effect a more cost efficient operation due to the lower requirements for personnel time expenditure.
In the operation of all types of refrigerated display cabinets, it is desirable to include a system for automatically defrosting the refrigeration coils. The defrost cycle can be actuated either at set periodic time intervals or when the frost build-up within the system has reached a certain predetermined level. Such systems are typically thermostatically controlled so as to switch from a refrigerated cycle to a defrost cycle of operation. In this manner of operation it is possible to avoid any significant frost build-up within the display cabinet such that inoperability and spoilage of food products would occur.
There have been three different approaches for defrosting refrigerated display cabinets in this art, utilizing the electric resistance heaters; passing a compressed refrigerant gas having a high specific heat through the refrigeration coils; and, circulating ambient air through an air conduit in which the refrigeration coils are positioned. Due to the increased cost of energy, efforts have been made to place more emphasis on the utilization of ambient air defrost systems as an alternative to the electric resistance heaters or compressed refrigerant gas defrost systems.
The present invention is useable with all three of these defrost systems. The automated protective barrier cover can be arranged for covering the access opening of refrigerated cabinets which also contain air defrost systems in such a manner that the cover is retracted automatically at the beginning of a defrost cycle in order to permit the flow of defrost air through the access opening of the cabinet. Such defrost cycles frequently occur during the non-customer use time periods during which the store is closed. Thus, the automated feature of the present invention permits the use of the protective barrier cover with air defrost refrigerated cabinets. In a manually arranged cover system such air defrost through the access opening is not practical since store personnel are not present during the periods when the store is closed.